| name | fsharp-diagnostics |
| description | Always invoke after editing `.fs` files under `src/Compiler/`. Fast parse/typecheck without `dotnet build`, plus symbol references and inferred type hints. Use whenever the user asks about F# errors, compile errors, type inference, finding usages, or renaming a symbol in the compiler tree. |
F# Diagnostics
Scope: src/Compiler/ files only.
Setup (once per session)
Requires pwsh 7+ (brew install powershell / winget install Microsoft.PowerShell / apt install powershell).
function GetErrors { & "$(git rev-parse --show-toplevel)/.github/skills/fsharp-diagnostics/scripts/get-fsharp-errors.ps1" @args }
From bash/zsh without a function: pwsh -File <repo>/.github/skills/fsharp-diagnostics/scripts/get-fsharp-errors.ps1 <args>.
Parse first, typecheck second
GetErrors -ParseOnly src/Compiler/Checking/CheckBasics.fs # syntax only
GetErrors src/Compiler/Checking/CheckBasics.fs # full typecheck
Fix all parse errors before typechecking; type errors on top of bad syntax are noise.
Symbol references (line 1-based, col 0-based)
GetErrors -FindRefs src/Compiler/Checking/CheckBasics.fs 30 5
Use before any rename.
Type hints (line range, 1-based)
Returns the range with inferred types as inline // (name: Type) comments:
GetErrors -TypeHints src/Compiler/TypedTree/TypedTreeOps.Transforms.fs 100 120
Other
GetErrors -CheckProject # typecheck entire project
GetErrors -Ping # liveness check, no side effects
GetErrors -Shutdown
Timing
- First real call after a fresh clone: server build + in-memory warmup, 5–15 min →
initial_wait=1200.
- After warmup: real commands answer in seconds →
initial_wait=180.
-Ping / -Shutdown: sub-second; never trigger build or warmup.
Auto-shuts down after 4h idle; ~3 GB RAM while running.
